Rock Calculator
Estimate how much landscape rock or river rock you need by cubic yards and tons for beds, borders, and ground cover.
Quick Answer
To estimate landscape rock, multiply length × width × depth in feet, divide by 27 for cubic yards, then multiply by about 1.4–1.5 for tons. One ton of rock covers roughly 70–100 sq ft at 2 inches deep, with larger stone covering less.
Rock Calculator (Landscape Rock by Yard & Ton) Guide
The rock calculator tells you exactly how much landscape rock to order—in cubic yards and tons—for beds, borders, dry creek beds, and decorative ground cover. Enter the area's length, width, and the depth you want, and it converts everything for you so you don't end up short or with a leftover pile.
How Much Rock Do You Need?
Multiply length × width × depth (in feet), then divide by 27 for cubic yards. Most landscape rock weighs about 1.3–1.5 tons per cubic yard, so multiply your cubic yards by roughly 1.4 for a tonnage order. Depth depends on rock size: 2 inches is enough for small decorative stone, while larger river rock and cobbles need 3–4 inches for full coverage.
Choosing the Right Landscape Rock
Smooth river rock suits water features and borders; lightweight lava rock is great for low-weight beds; and angular crushed rock locks together for paths and driveways. For smaller, finer cover, compare options with our decorative stone calculator or plan a whole yard with the landscape stone calculator.
How Many Tons in a Cubic Yard of Rock?
Landscape rock weighs about 1.4 tons per cubic yard, so one cubic yard is roughly 1.4 tons. Larger, denser stone runs closer to 1.5 tons, while lightweight lava rock is far less (about 0.8 tons).
Rock coverage per ton by size (at 2 inches deep):
| Rock size | Coverage per ton |
|---|---|
| Small (½–1½ in) | ≈ 100–120 sq ft |
| Medium (1½–3 in) | ≈ 80–100 sq ft |
| Large (3–5 in) | ≈ 60–80 sq ft |
| Very large (6 in+) | ≈ 25–50 sq ft |
Crushed Rock vs Landscape Rock
The two names get used interchangeably, but they behave differently once they are on the ground. Crushed rock is mechanically broken, so every piece is angular and the edges lock together — that is what makes it hold a surface under foot or tyre traffic, and why it is the choice for paths, driveway bases and compacted layers. Landscape rock usually means rounded, decorative material such as river rock or cobbles, which stays loose underfoot but looks better in beds and borders.
The estimating maths is identical for both — area × depth, converted to cubic yards and tons — but crushed rock needs a compaction allowance of roughly 20–25% extra volume because it settles when compacted, while decorative rock is laid loose and needs none. If your project is a compacted base rather than ground cover, the crushed stone calculator and stone compaction calculator apply that allowance for you.
Estimating Rock for a Garden Bed
Garden beds are rarely simple rectangles, which is where most estimates go wrong. Break an irregular bed into rectangles and circles, work out each piece separately, then add the results. For a curved border, measuring the average width along its length is accurate enough — the error is far smaller than the variation between one supplier's rock and another's.
A 2-inch depth is enough for decorative cover in a planted bed, and going deeper mostly wastes material. Beds with no planting, where the rock is the whole surface, benefit from 3 inches over a weed barrier. For a full-yard plan across several beds and paths, the landscape stone calculator handles multiple areas at once.
How Much Does Landscape Rock Weigh?
Rock is ordered by volume but delivered by weight, so the conversion decides what turns up on the truck. Most landscape rock runs 1.3–1.5 tons per cubic yard. To go from volume to weight, multiply cubic yards by the figure for your material; to go the other way, divide. For weight of individual stones or slabs rather than bulk material, use the stone weight calculator.
Weight by rock type:
| Rock type | Tons per cubic yard | Lbs per cubic yard |
|---|---|---|
| River rock | 1.45 | ≈ 2,900 |
| Crushed rock / stone | 1.50 | ≈ 3,000 |
| Cobbles | 1.45 | ≈ 2,900 |
| Pea gravel | 1.35 | ≈ 2,700 |
| Lava rock | 0.78 | ≈ 1,560 |
Sources & Methodology
Volume-to-weight results use standard aggregate bulk densities (for example, crushed stone ≈ 1.5 US tons per cubic yard) applied consistently across this site, and pricing reflects 2026 U.S. supplier averages that vary by region and delivery. All results are planning estimates — confirm the exact density and price with your local supplier before ordering.
Frequently Asked Questions
How much area does a ton of landscape rock cover?
At a 3-inch depth, one ton of rock covers roughly 70–90 square feet, since a ton is about 0.7 cubic yards. Spread thinner at 2 inches, the same ton covers closer to 110–130 square feet. Larger rock and deeper coverage reduce the area per ton.
How deep should landscape rock be?
For small decorative stone, 2 inches gives full coverage. For larger river rock or in high-traffic areas, use 3–4 inches. Laying a weed barrier fabric underneath keeps the rock clean and stops it sinking into the soil.
How much does a cubic yard of rock weigh?
Most landscape rock weighs about 2,600–3,000 pounds per cubic yard (1.3–1.5 tons). Denser river rock sits at the heavier end, while porous lava rock is much lighter at roughly 1,500 pounds per cubic yard.
What is the difference between rock and gravel?
Gravel is small (typically under 1 inch) and often used for paths and bases, while landscape rock covers a wider range of larger decorative stones like river rock and cobbles. Both are estimated the same way—by area and depth.
How much crushed rock do I need?
Multiply length × width × depth in feet, divide by 27 for cubic yards, then multiply by about 1.5 for tons. Add 20–25% extra volume if the rock will be compacted, because it loses that much thickness under a plate compactor. A 20 × 10 ft path at 3 inches needs about 1.85 cubic yards loose, or roughly 2.3 cubic yards ordered for a compacted finish.
How much rock do I need for a garden bed?
Measure the bed's length and average width, multiply by a 2-inch depth (0.167 ft), and divide by 27 for cubic yards. A 12 × 4 ft bed needs about 0.3 cubic yards, or roughly 0.42 tons. Break irregular beds into rectangles and add the results together.
Is crushed rock the same as landscape rock?
Not quite. Crushed rock is angular and locks together when compacted, which suits paths, bases and driveways. Landscape rock usually means rounded decorative stone such as river rock, which stays loose and is used for beds and borders. Both are estimated by area and depth, but only crushed rock needs a compaction allowance.
Slopes, Low Spots & Uneven Ground
Any calculator assumes a flat rectangle at a uniform depth. Real ground rarely is, and that difference — not arithmetic — is what usually causes a second delivery. Three site conditions are worth checking before you order.
Sloped ground
A slope has more surface area than its footprint suggests, and loose material migrates downhill and piles at the bottom. Measure the distance along the slope rather than the flat map distance, and add roughly 10% on a gentle grade or 15–20% on anything noticeably steep. On slopes above about 15% consider edging or a retaining course — otherwise the stone ends up at the bottom regardless of how much you order.
Low spots and ruts
Depressions swallow far more material than their size suggests, because you are filling a void before you start building depth. A rut 10 ft long, 2 ft wide and 4 inches deep holds about 0.25 cubic yards on its own — roughly a third of a ton — none of which contributes to your finished surface. Measure significant low spots separately, add them as their own volume, and consider filling and compacting them first.
Soft or uneven subgrade
On soft ground the first layer of stone pushes down into the soil instead of building up. That loss is real and hard to predict — on soft clay or freshly disturbed earth it can absorb a half-inch or more of your base. Compacting the subgrade first, or laying geotextile fabric, keeps the stone where you put it and is cheaper than the extra material.
The rule of thumb
Order about 10% more than the calculated figure on flat, prepared ground, and up to 20% on sloped or uneven sites. Running slightly over costs a little; running short means a second delivery fee, often for a fraction of a load, and a visible seam where the work stopped.
Getting It Delivered
Knowing your tonnage is only half the job — the other half is whether that amount is a sensible thing to order. Suppliers sell in load sizes, not in whatever number a calculator produces, and the gap between the two is where budgets slip.
| Method | Typical capacity | Best for |
|---|---|---|
| Pickup truck (own transport) | ≈ 1 cubic yard | Small repairs and top-ups |
| Bulk bag (supersack) | ≈ 1 yd³ / 1.4 tons | Anything under about 2 tons |
| Standard dump truck | ≈ 10–16 tons | Driveways, patios, most home projects |
| Large tri-axle | up to ≈ 25 tons | Full driveway rebuilds, bulk base |
Swipe horizontally to see all columns →
If your total comes to under about 2 tons
Ask about bulk bags before booking a truck. Many suppliers apply a minimum load — commonly in the region of 5 to 10 tons for free local delivery — so a small order can end up paying a delivery fee that costs more than the stone itself. Bagged or collected material is often the cheaper route at that scale.
If your total lands just over a load size
Round to the load rather than ordering a second part-load. Needing 17 tons usually means paying for two deliveries; trimming the depth slightly, or accepting a marginally thinner finish in a low-traffic area, can bring the job inside one. Confirm the actual load capacity with your supplier, as it varies with vehicle type and local axle-weight limits.
Before the truck arrives
Check access height and width, and decide exactly where the pile goes — moving several tons by barrow because the driver could not reach the spot is the single most avoidable cost on a delivery day. Ask whether the truck tips in one heap or can spread along a driveway, since that changes the labour considerably.
Capacities are typical figures and vary by supplier, vehicle and local weight limits. Prices vary too widely by region and season to quote usefully — get a current quote for your postcode before budgeting.
Sources & Methodology
This calculator uses standard published conversion factors and material densities. Density figures are typical values — actual material varies by quarry, moisture content and compaction, so treat results as estimates and confirm quantities with your supplier before ordering.
- Pavements and Pavement Design — U.S. Federal Highway Administration
Federal guidance on aggregate base layers, compaction and subgrade preparation.
- National Ready Mixed Concrete Association — NRMCA
Industry reference for aggregate proportions, yields and unit weights.
- British Geological Survey — BGS
Reference data on UK building stone types and their physical properties.
Reviewed by the Stone Calculator editorial team
Last updated: